Method of mulling and heat-setting in shoe manufacture



Oct. 31, 1967 c. K. WOODMAN 3,349,417

METHOD OF MULLING AND HEAT-SETTING IN SHQE MANUFACTURE Filed Aug. 27, 1965 2 Sheets-Sheet 1 INVENTOR. 0 fill/695K. h balmm .1 7 BY 2 J I 7 fl flf/"VJ Oct. 31, 1967 c, K. WOODMAN 3,349,417

METHOD OF MULLING AND HEAT-SETTING IN SHOE MANUFACTURE Filed Aug. 2'7, 1965 2 Sheets-Sheet 2 United States Patent 3,349,417 METHOD OF MULLING AND I-lEAT-SEITIN G IN SHOE MANUFACTURE Charles K. Woodman, Beverly, Mass., assignor to Compo Shoe Machinery Corporation, Waltham, Mass., a corporation of Delaware Filed Aug. 27, 1965, Ser. No. 483,278 22 Claims. (Cl. 12142) ABSTRACT OF THE DISCLOSURE A method of heat-treating and heat-setting a shoe comprising first wetting the shoe to establish a substantially known moisture content and then drying the shoe by first evaporating moisture therefrom in a stream of heated air and then cooling the shoe in a stream of ambient air to eliminate surface plasticity.

A great deal of time and effort is expended in shoe making to cause the upper material to conform intimately to the surface contour of the last, whether the surface is flat or curved, and, when curved, whether it is convex or concave; to remove wrinkles and looseness; and to set the upper when it has been drawn into intimate contact with the last so that it will retain the shape imparted thereto by such expedients as mulling and/ or heat-setting, in which the upper assembly embodying an outer, lining and/ or counter off or on the last is completely or partial ly saturated with water and thereafter completely or partially dried under controlled conditions of humidity and temperature. In spite of what has been done up to this point, satisfactory elimination of wrinkles and permanent setting of the natural upper materials to the last and especially permanent setting of the newer man-made materials has not been achieved.

The principal objects of this invention are to obtain smooth wrinkle-free, tight-fitting uppers which permanently retain the contour imparted to them whether they are comprised of natural or man-made materials; to provide a method of achieving the foregoing with not too critical limits of time, temperature and moisture content thereby to avoid the need for expensive equipment and sensitive controls; to provide a method of achieving the foregoing without damage to the materials of which the shoes are made and off or on the last; to provide a method in which the mulling of the upper off the last or on the last can be performed just before the lasting operation or after lasting and just before the setting operation so that regardless of the previous condition of the shoe a predictable amount of moisture is present during lasting and/or setting; to provide a method which is especially beneficial in setting shoes in which the counter contains a large amount of water where, for example, water paste or latex is employed and the water soaks into the counter; and to provide a method which is adapted especially to treating the back parts of shoes.

In accordance with the foregoing objects the method comprises treating shoe uppers embodying an outer material, lining and counter with a wetting agent to render it conductive of moisture and then force-drying the uppers. Wetting oftthe upper material to render it conductive of moisture may be carried out prior to lasting of the upper to the last whereupon the drying will be effected while the upper remains on the last. According to the preferred method, the upper is rendered conductive by application of the wetting agent after the upper has been lasted to the last and drying is effected on the last. Following drying the upper is subjected to cooling to lower its temperature to a temperature below the plasticity of the upper material. Wetting is preferably achieved by spraying a mixture of water and wetting agent on the surface of the upper and drying is achieved with a forced draft of air at a temperature above ambient temperature but below that which would be destructive of the upper material. Specifically, the wetting is effected by spraying the upper with a solution containing approximately of 1% to 2% wetting agent delivered at a rate of about 1 gallon per hour, forced draft drying is effected in a current of air flowing at approximately 4000 feet per minute and at a temperature within the range of 175 to 300 F., and forced draft cooling is effected in a current of air travelling at approximately 2500 feet per minute. The shoes are treated to the successive operations of spraying, drying and cooling for periods of approximately eight (8) seconds, ninety to one-hundred and thirty and thirty (30) seconds respectively.

The invention will now be described in greater detail with reference to the accompanying drawings in which there is shown apparatus which may be employed to practice the method of this invention and wherein:

FIG. 1 diagrammatically shows a lasted shoe movable successively from a first position for spraying to a second position for forced draft drying and a third position for forced draft cooling;

FIG. 2 diagrammatically shows an unlasted shoe movable successively from a first position for spraying to a second position after lasting and on the last forced draft drying and a third position for forced draft cooling;

FIG. 3 is a top view of an apparatus for successively treating shoes to spraying, drying and cooling;

FIG. 4 is a fragmentary vertical section at the loading and unloading position of the apparatus shown in FIG. 1, showing spray guns mounted to spray the back parts of shoes supported in the apparatus;

FIG. 5 is a fragmentary plan view at the loading and unloading position of the apparatus shown in FIG. 1, showing cam means for actuating the spray guns; and

FIG. 6 illustrates an apparatus which may be mounted adjacent a pulling-over or lasting machine for spraying upper assemblies prior to pulling-over and lasting.

In FIG. 1 the successive steps of the method are shown to be linear, that is, along a straight line; however, in actual practice it is preferred to provide means for sup porting pairs of lasted shoes for movement about a common center relative to treating stations for spraying with an aqueous solution, force-drying in a current of heated air and force-cooling in the current of cool air, so that the operator can load and unload the apparatus from a single vantage point.

Starting with a lasted shoe (FIG. 1), the method is practiced by subjecting or exposing the shoe 10, while still on its last L, to an application of moisture by spraying the bottom and sides, particularly at the back part of the shoe, with water containing a wetting agent or detergent. The shoe will normally be at ambient temperature and it is preferable to apply the mixture of water and wetting agent or detergent at approximately the same temperature with a spray gun 12, or like device, by means of which it may be atomized.

The solution is sprayed from the spray gun 12 at a rate of about one gallon per hour and the shoes are exposed to the spray for a period of approximately eight seconds. The wetting agent or detergent present in the water is in the proportion of about of 1% to 2% of the solution.

Preferably the wetting agent or detergent solution is sprayed onto the shank, heel seat and back line are-as of the shoe while the latter is supported bottom side up. Optionally, following this spraying operation the upper may be subjected to additional moisturizing with a water vapor.

Having thoroughly wet the shoe with the foregoing solution, the shoe is now moved to a place 14 for forced draft drying in a current of heated air and is exposed at this place for a period of about ninety to one-hundred and thirty seconds to a current of air travelling at the rate of about 4000 feet per minute. The air is heated, that is, is above the temperature of the ambient air but below a temperature which would be destructive of the upper material. For natural materials, that is, leather uppers, a temperature of 200 to 250 F. is preferred. For manmade materials, such as Corfam, a temperature of 275 F. is employed. With the shoes supported bottom up, the best results are achieved by flow of the drying air toward the bottom of the shoes, that is, downwardly as herein shown over the bottoms and about the sides of the uppers.

Following drying which sets the upper material to the wood of the last, the shoe is moved to a place 16 for forced draft cooling in a current of cool air so as to remove any plasticity in the surface of the material which might become marked by laying the shoe down following treatment. At this place, the shoe is subjected to a draft of cooling air for a period of approximately thirty seconds, travelling at a rate of approximately 2500 feet per minute and preferably directed against the bottom of the shoe so that it flows downwardly over the bottom and then about the sides. The cooling air may be drawn from the room and thus be at ambient temperature or may be artificially cooled.

The use of the water wetting agent solution materially improves the rate of penetration of the water into the upper material so as to obtain uniformity in stress throughout and is especially beneficial during heat-setting as it provides an avenue or path for the moisture to escape more rapidly during drying and setting and hence shorten drying time. The establishment of this path is also especially beneficial in allowing water to be drawn from a wet counter or lining through the outer during setting and thus obtaining much shorter setting periods in shoes wherein the lining and/ or counter is mulled and/ or secured with a water base paste or latex. In fact, it is desirable not only to wet the upper with the solution but also the lining and counter to provide a continuous avenue of escape for the moisture from the inside of the shoe outwardly.

About 80% of the usual wrinkles in shoes with leather uppers and looseness in both leather and man-made uppers may be materially reduced by application of an aqueous solution of wetting agent or detergent to the uppers followed by heat-setting and cooling, as related above, with or without treatment of the upper intermediate the wetting and the heat-setting with a moist vapor.

As herein illusrated, the mulling and setting of the shoes is carried out in a machine which, as shown in FIGS. 3, 4 and 5, embodies a rotor 18 provided with a plurality of radially extending vanes 20 disposed in a circular housing 22, the latter having an opening 24 at one side. The vanes 20 provide compartments circumferentially of the axis of rotation of the rotor and within each compartment there are supports 26 (FIG. 4) for receiving and supporting two shoes bottom side up for movement in rotation with the rotor. The shoes are mounted on the supports 26 in the compartments as they move through the openings 24 and following treatment are removed from the compartment through the same opening. In the preferred form of the apparatus, a pair of spray guns 28 (FIGS. 4 and are mounted adjacent the opening 24 for spraying the shoes just before they enter the housing 22. The spray guns may be operated manually or they may be cam-operated by rotation of the rotor 18 to trigger the spray gun for a period of time sufficient to apply the correct amount of mixture to them.

The rotor as related above is provided with a plurality of compartments and the extreme edges of the vanes 20 are provided with sealing strips 30 so that successive places of operation are sealed from each other. Preferably each compartment moves through an air lock into the housing an amount W (FIG. 3) corresponding to its own width before the succeeding operation of drying takes place. This is primarily to provide a seal between the opening 24 and the interior of the housing so that the drying air will not leak out and be wasted and to permit the moisture to become assimilated in substantial equilibrium throughout the upper. Beyond the air lock and extending, for example, a distance X (FIG. 3), a draft of heated air is pumped through the chamber from top to bottom by means of a pump (not shown) located centrally of the rotor. Pumping of the air through the compartment is maintained while the rotor continues to rotate the compartment through the distance X, as pointed out above, so as to expose the shoes to the forced draft hot air for a period of ninety to one-hundred and thirty seconds. At the end of this portion of rotation, the compartment will again be sealed in a second air lock for a distance Y corresponding to one or more compartments and then will be exposed just before it reaches the left-hand side of the opening 24 to a current of cooling air, for a distance Z which may be one or more compartments in width at atmospheric temperature for a period of approximately thirty seconds.

Apparatus of the foregoing kind is primarily suited to carrying out the method on shoes that have been completely lasted and are ready for attachment of their bottoms to make sure that the lasting stresses produced by lasting are relieved so that the upper does not want to return to its unstretched condition when removed from the last and hence will permanently retain the contour of the last.

As related above, the method is also applicable in the manufacture of shoes wherein the mulling is carried out prior to pulling-over and lasting and the setting is carried out following lasting. Thus, unlasted uppers 10a (FIG. 2) may be subjected to spraying with water containing a wetting agent prior to pulling-over or lasting, employing the same conditions, that is, the same proportions of water and wetting agent, the same temperatures of the upper material and spraying solution and the same time for exposure to effect wetting. The wet or moisturized uppers are now assembled on lasts, pulled-over in pulling-over machines, lasted on lasting machines and then placed in the rotary machine referred to above wherein withdrawal of the moisture and setting is effected. When practicing this procedure, the spray guns may be disabled so that the shoes placed in the compartments move into the sphere of forced draft drying without being exposed to additional wetting. However, if the shoes need the extra wetting, they should be sprayed before drying.

An appartus convenient for wetting the uppers just before they are mounted on lasts for pulling-over is shown in FIG. 6 which comprises a hollow rectangular housing 30a, in one wall of which is supported one or more spray guns 32. An open side receptacle 34 is slidably supported in the housing 30 for movement horizontally through the housing. The receptacle 34 is divided intermediate its ends by a partition wall 36 and within each end there is mounted a hook 38 on which the unlasted upper may be suspended. The device is mounted, for example, by means of a bracket 40 on an assembling machine and provides means for constantly supplying the operator with a properly mulled upper for the pullingover and subsequent lasting operations. Operation is effected by sliding the receptacle 34 horizontally to a first position to expose one half, suspending an upper on the hook in this one half and then shifting the receptacle to expose the other half and to hang an upper within this other half. While the receptacle is in the first position, the spray gun or guns are operated for a predetermined length of time to spray the upper within the other half. Correspondingly, when the receptacle is moved to the other position the spray gun will be actuated to spray the upper in the one half while the operator removes the sprayed upper from the other half for use and replaces it with another upper for treatment.

The method as herein disclosed is not dependent for its accomplishment upon the apparatus herein disclosed and hence is not to be considered in any Way to be limited by the structural features or mode of operation of the illustrated apparatus. In its broadest sense, the method embodies applying a water and wetting agent mixture in the form of a spray on the surface of the upper for a period of time sufiicient to provide a path or avenue for the moisture to leave the upper material during drying, of then forced draft drying the upper in rapidly flowing heated air which is not so high as to be destructive of the upper, and finally forced draft cooling of the upper to ambient temperature to eliminate surface plasticity. The foregoing treatment removes strains successively imparted to the upper during lasting so that the material has no tendency to return to its initial dimension, reduces wrinkles and loosens in leather uppers, reduces regain in man-made materials, and imparts permanence to the shape of both natural and man-made materials.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. The method of treating lasted shoes while still on the lasts and which embody an outer material, a lining and a heel counter adhesively united by a water base adhesive, comprising adding a sufficient amount of wetting agent to the exterior of the outer material to penetrate to the interior of the outer material, forced draft drying the shoe by means of heated air, and then forced draft cooling the shoe to a temperature such that thesurface plasticity is eliminated.

2. The method of treating shoes after lasting and while they remain on the last comprising adding a wetting agent to the upper to provide an avenue for the escape of moisture in the upper, and forced draft drying the upper to cause it to conform intimately to the surface of the last by first forced draft drying the upper by means of heated air and then forced draft cooling the upper to a temperature below that at which the surface is plastic.

3. The method of mulling and heat-setting comprising spraying the external surface of the shoe at ambient conditions with Water at ambient temperature containing a wetting agent, subjecting the sprayed shoe to forced draft drying with air at a temperature above the temperature of the ambient air but below a temperature which would be destructive of the upper material, and then subjecting the shoe to forced draft cooling to remove any plasticity at the surface of the shoe.

4. The method of mulling and heat-setting comprising spraying the external surface of a lasted shoe on the last and at ambient conditions with water at ambient temperature containing a wetting agent, subjecting the sprayed shoe to forced draft drying with air at a temperature above the temperature of the ambient air but below the temperature which would be detrimental to the upper material, and then subjecting the shoe while still on the last to forced draft cooling with air to eliminate surface plasticity.

5. The method of mulling and heat-setting comprising spraying the external surface of a shoe with a fine spray of water containing a wetting agent, subjecting the sprayed shoe to forced draft drying with air at a temperature above the temperature of the ambient air but below a a temperature which would be detrimental to the upper material, and then subjecting the shoe to forced draft cooling with air to lower the temperature of the shoe to a temperature such that the surface plasticity is removed.

6. The method of mulling and heat-setting comprising exposing the external surface of a shoe to a fine spray of water containing a wetting agent ejected from an orifice at the rate of approximately one gallon per hour for approximately eight seconds, subjecting the sprayed shoe to forced draft drying with air at a temperature above the temperature of the ambient air but below a tempera- 5 ture which would be detrimental to the upper material and then subjecting the shoe to forced draft cooling to lower the temperature of the shoe to a temperature below the temperature at which the surface is plastic.

7. The method of mulling and heat-setting comprising exposing the external surface of a shoe to a fine spray of water containing a wetting agent in the proportion of about of 1% to 2% of the mixture, subjecting the sprayed shoe to forced draft drying with air at a temperature above the temperature of ambient air but below a temperature which would be detrimental to the upper material, and then subjecting the shoe to forced draft cooling with air to lower the temperature of the shoe substantially to that of the ambient air.

8. The method of mulling and heat-setting comprising exposing the exterior surface of a shoe for approximately eight seconds to a fine spray of water containing of 1% to 2% wetting agent, delivered at the rate of about one gallon per hour, subjecting the sprayed shoe to forced draft drying with air at a temperature above the ambient air but below a temperature which would be detrimental to the upper material, and then subjecting the shoe to forced draft cooling to lower the temperature of the shoe to that of the ambient air.

9. The method of mulling and heat-setting comprising subjecting the exterior surface of a shoe to a fine spray of water containing a wetting agent, subjecting the sprayed shoe to forced draft drying in a current of air flowing at the rate of approximately 4000 feet per minute and at a temperature above the temperature of the ambient air and below that which would be detrimental to the upper material, and then subjecting the dried shoe to forced draft cooling in a current of air to lower the temperature of the shoe substantially to that of the ambient air.

10. The method of mulling and heat-setting comprising subjecting the exterior surface of a shoe for a period of approximately eight seconds'to a fine spray of water containing a wetting agent delivered at the rate of approximately one gallon per hour, subjecting the sprayed shoe to forced draft drying in a current of air flowing at approximately 4000 feet per minute and at a temperature within the range of 175 to 300 F., and then subjecting the shoe to forced draft cooling with air to lower the temperature of the shoe substantially to that of the ambient air.

11. The method of mulling and heat-setting comprising subjecting the exterior surface of a shoe for a period of approximately eight seconds to a fine spray of water containing a Wetting agent and delivered at the rate of ap- 55 proximately one gallon per hour, subjecting the sprayed shoe to forced draft drying in a current of air flowing at a rate of approximately 4000 feet per minute and at a temperature in the order of 200 to 250 F., and then subjecting the shoe to forced draft cooling with air to lower 0 the temperature of the shoe to that of the ambient air.

12. The method of mulling and heat-setting comprising subjecting the exterior surface of a shoe for a period of approximately eight seconds to a fine spray of water containing a wetting agent delivered at the rate of ap- 55 proximately one gallon per hour, subjecting the sprayed shoe to forced drying in a current of air flowing at approximately 4000 feet per minute and at a temperature of approximately 275 F., and then subjecting the shoe to forced draft cooling with air to lower the temperature of 70 the shoe to that of the ambient air.

13. The method of mulling and heat-setting comprising exposing the exterior surface of a shoe unconfined and at ambient conditions to a fine spray of water containing a wetting agent, moving the shoe into a confining chamber,

75 exposing the shoe while in said confining chamber to forced draft drying in a current of air travelling at a rate of approximately 4000 feet per minute, moving the dried shoe from the drying chamber to a confining cooling chamber for cooling, and subjecting the dried shoe to forced draft cooling in a current of air to lower the temperature of the shoe to ambient temperature.

14. The method of mulling and heat-setting comprising exposing the exterior surface of a shoe unconfined and at ambient conditions to a fine spray of water containing a wetting agent, moving the sprayed shoe through confining chambers and successively exposing the shoes in said chambers to drying in a draft of air travelling at a rate of 4000 feet per minute and at a temperature of 175 to 300 F., and then to cooling in a draft of air travelling at 2500 feet per minute and at ambient temperature, and moving said shoe through said successive places of treatment at a rate such as to be exposed to the heating for a period of 90 to 130 seconds and to cooling for approximately 30 seconds.

15. The method of shoe making comprising subjecting an upper unit of natural material to wetting with a wetting agent, lasting the Wet upper, forced draft drying the wet upper while still on the last to release the lasting stresses, to set the upper to the surface of the last and removing wrinkles, and forced draft cooling the heat-set upper to ambient temperature to eliminate surface plasticity.

16. A method according to claim 15, wherein the upper unit includes a lining and/ or counter.

17. The method of shoe making comprising subjecting an upper unit of man-made material to wetting with a wetting agent, lasting the wet upper, forced draft drying the Wet upper while still on the last to relieve the lasting strain and to set the upper to the surface of the last, and forced draft cooling the heat-set upper to a temperature such as to remove surface plasticity.

18. The method of treating lasted shoes while still on a last, comprising applying a wetting agent to the bottom and back line of the heel, forced draft drying the upper by placing the shoe in a current of heated air flowing -in a direction toward the bottom side and away from the top side and then forced draft cooling the upper by placing the shoe in a current of air at ambient temperature flowing in a direction toward the bottom side and away from the top side.

19. The method of treating lasted shoes while still on a last, comprising ejecting from a spray head a fine spray of wetting agent, supporting a lasted upper with its bottom confronting the spray head, so that the bottom intercepts the sprayed Wetting agent and simultaneously shields the upper from direct impingement of the sprayed wetting agent thereon, and then forced draft drying the shoe in a current of air flowing in a direction toward the bottom side of the shoe and away from the top side thereof.

20. The method according to claim 19, comprising placing the shoe following wetting with the wetting agent in a first draft of heated air to effect drying and then in a second draft of cooling air to effect cooling.

21. The method according to claim 19, comprising confining the current of air within which the shoe is placed so that it impinges upon the bottom of the shoe, flows laterally over the peripheral edge of the bottom about the sides and away from the top of the shoe.

22. The method of treating shoes while still on a last comprising spraying the bottom with a water containing a wetting agent, evaporating the water from the bottom leaving the wetting agent thereon by placing the shoe in a stream of heated air and exposing the upper-to the moisture-laden heated air during drying by supporting the shoe in the stream with the bottom confronting the stream so that the air impinges first upon the bottom, flows over the edges and then along the sides and leaves the shoe at the top.

References Cited UNITED STATES PATENTS 3,220,036 ll/1965 Bromfield et a1. 12-l42 3,237,227 1/1966 Bromfield 12--142 FOREIGN PATENTS 438,123 11/1935 Great Britain.

PATRICK D. LAWSON, Primary Examiner. 

1. THE METHOD OF TREATING LASTED SHOES WHILE STILL ON THE LASTS AND WHICH EMBODY AN OUTER MATERIAL, A LINING AND A HEEL COUNTER ADHESIVELY UNITED BY A WATER BASE ADHESIVE COMPRISING ADDING A SUFFICIENT AMOUNT OF WETTING AGENT TO THE EXTERIOR OF THE OUTER MATERIAL TO PENETRATE TO THE INTERIOR OF THE OUTER MATERIAL, FORCED DRAFT DRYING THE SHOE BY MEANS OF HEATED AIR, AND THEN FORCED DRAFT COOLING THE SHOE TO A TEMPERATURE SUCH THAT THE SURFACE PLASTICITY IS ELIMINATED. 